In the display arts, image contrast can affect the perceived dynamic range of displayed image data. Increasing or decreasing the contrast settings can present image data to be more or less visually stimulating. Un-adapted or uncorrected image signals can hide details of the image. Conventional approaches of adjusting contrast settings of a display device may employ an overall contrast setting, such as a brightness control, for complete adjustment of image data to be displayed. These adjustments however, may be too severe and can result in washout of the image.
Attempts have been made to modify the conventional approaches through adaptive contrast adjustment of image data. However, these attempts for adjusting the contrast can result in negative effects. For example, some contrast adjustment methods and devices create visual artifacts in enhanced image. Similarly, these adjustment methods can result in data cut-off in dark in bright pixel levels, degradation of dark scenes due to improper adjustment and even flickering. Additionally, performing contrast adjustment for color spaces may result in difficulty of maintaining a white balance due to non-linear gamma correction. Further, the cost of contrast adjustment in additional color spaces and accuracy of multiple conversions may be prohibitive.
Thus, there is a need in the art for an apparatus and methods of adaptive contrast which provides adaptive contrast of image data while increasing the dynamic range.